Solid-state imaging device

ABSTRACT

A solid-state imaging device having a first area and a second area surrounding the first area is provided. The solid-state imaging device includes a substrate having a plurality of photoelectric conversion elements. The solid-state imaging device also includes a color filter layer disposed on the substrate. The color filter layer includes a plurality of color filter segments corresponding to the plurality of photoelectric conversion elements. The solid-state imaging device further includes an optical waveguide layer over the color filter layer. The optical waveguide layer includes a waveguide partition grid, a waveguide material in spaces of the waveguide partition grid, and an anti-reflection film on the waveguide partition grid and the waveguide material. The width of the top of the waveguide partition grid is larger than the width of the bottom of the waveguide partition grid.

BACKGROUND Technical Field

The embodiments of the present disclosure relate to an imaging device,and in particular they relate to a solid-state imaging device thatincludes a waveguide partition grid having variable widths.

Description of the Related Art

Solid-state imaging devices, such as charge-coupled device (CCD) imagesensors and complementary metal-oxide semiconductor (CMOS) imagesensors, have been widely used in various image-capturing apparatusessuch as digital still-image cameras, digital video cameras, and thelike. In these solid-state imaging devices, a light-sensing portion isformed at each of a plurality of pixels, and signal electric charges aregenerated according to an amount of light received in the light sensingportion. In addition, the signal electric charges generated in the lightsensing portion are transmitted and amplified, whereby an image signalis obtained.

Recently, the trend has been for the pixel size of solid-state imagingdevices typified by CMOS image sensors to be reduced for the purpose ofincreasing the number of pixels to provide high-resolution images.However, while pixel size continues to decrease, there are still variouschallenges in the design and manufacturing of solid-state imagingdevices.

BRIEF SUMMARY

In (or near) the edge area or the peripheral area of the solid-stateimaging device, incident lights radiating into the solid-state imagingdevice may be oblique and the sensitivities of the photoelectricconversion elements may be non-uniform due to the different refractiveindexes of the different color filter segments. In the embodiments ofthe present disclosure, the solid-state imaging device includes awaveguide partition grid having different grid widths, which may improvethe uniformity of the pixel sensitivities in the edge area or theperipheral area of the solid-state imaging devices.

In accordance with some embodiments of the present disclosure, asolid-state imaging device having a first area and a second areasurrounding the first area is provided. The solid-state imaging deviceincludes a substrate having a plurality of photoelectric conversionelements. The solid-state imaging device also includes a color filterlayer disposed on the substrate. The color filter layer includes aplurality of color filter segments corresponding to the plurality ofphotoelectric conversion elements. The solid-state imaging devicefurther includes an optical waveguide layer over the color filter layer.The optical waveguide layer includes a waveguide partition grid, awaveguide material in spaces of the waveguide partition grid, and ananti-reflection film on the waveguide partition grid and the waveguidematerial. The width of the top of the waveguide partition grid is largerthan the width of the bottom of the waveguide partition grid.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be more fully understood from the following detaileddescription when read with the accompanying figures. It is worth notingthat, in accordance with standard practice in the industry, variousfeatures are not drawn to scale. In fact, the dimensions of the variousfeatures may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a top view illustrating a solid-state imaging device accordingto some embodiments of the disclosure.

FIG. 2A is a partial plane view illustrating area ROI-1 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 2B is a partial plane view illustrating area ROI-2 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 2C is a partial plane view illustrating area ROI-3 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 3A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 3B is a partial cross-sectional view illustrating area ROI-2 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 3C is a partial cross-sectional view illustrating area ROI-3 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 4A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 4B is a partial cross-sectional view illustrating area ROI-3 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 5A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 5B is a partial cross-sectional view illustrating area ROI-3 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 6A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 6B is a partial cross-sectional view illustrating area ROI-3 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 7A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 7B is a partial cross-sectional view illustrating area ROI-3 of thesolid-state imaging device according to some embodiments of thedisclosure.

FIG. 8A is a partial cross-sectional view illustrating the solid-stateimaging device according to some embodiments of the disclosure.

FIG. 8B is a partial cross-sectional view illustrating the solid-stateimaging device according to some embodiments of the disclosure.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the subject matterprovided. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, a firstfeature is formed on a second feature in the description that followsmay include embodiments in which the first feature and second featureare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first feature and secondfeature, so that the first feature and second feature may not be indirect contact.

It should be understood that additional steps may be implemented before,during, or after the illustrated methods, and some steps might bereplaced or omitted in other embodiments of the illustrated methods.

Furthermore, spatially relative terms, such as “beneath,” “below,”“lower,” “on,” “above,” “upper” and the like, may be used herein forease of description to describe one element or feature's relationship toother elements or features as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

In the present disclosure, the terms “about,” “approximately” and“substantially” typically mean +/−20% of the stated value, moretypically +/−10% of the stated value, more typically +/−5% of the statedvalue, more typically +/−3% of the stated value, more typically +/−2% ofthe stated value, more typically +/−1% of the stated value and even moretypically +/−0.5% of the stated value. The stated value of the presentdisclosure is an approximate value. That is, when there is no specificdescription of the terms “about,” “approximately” and “substantially”,the stated value includes the meaning of “about,” “approximately” or“substantially”.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It shouldbe understood that terms such as those defined in commonly useddictionaries should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art andwill not be interpreted in an idealized or overly formal sense unlessexpressly so defined in the embodiments of the present disclosure.

The present disclosure may repeat reference numerals and/or letters infollowing embodiments. This repetition is for the purpose of simplicityand clarity and does not in itself dictate a relationship between thevarious embodiments and/or configurations discussed.

In solid-state imaging devices, an incident light radiates onto theedges (peripheral area) of a pixel array at an oblique angle that isgreater than a normal angle of the incident light radiating onto thecentral area of the pixel array. The angles of the incident light aredetermined from the normal line of a light-receiving surface of thesolid-state imaging devices. For example, an oblique angle of anincident light radiating onto the edges (peripheral area) of the pixelarray may be about +/−20 degrees to about +/−40 degrees, and the normalangle of the incident light radiating onto the central area of the pixelarray may be about 0 degrees.

Solid-state imaging devices are roughly classified into two groups interms of the direction of light incident on a light receiving unit. Oneis the front-side illuminated (FSI) imaging devices that receive lightincident on the front side of a substrate on which the wiring layer ofthe reading circuit is formed. Another is the back-side illuminated(BSI) imaging devices that receive light incident on the back side of asemiconductor substrate on which no wiring layer is formed. For imaginga color image, a color filter is provided in the FSI and BSI imagingdevices. The FSI and BSI imaging devices usually have a light-shieldinggrid structure for blocking light between pixels to prevent colormixture.

FIG. 1 is a top view illustrating a solid-state imaging device 100according to some embodiments of the disclosure. Referring to FIG. 1,area ROI-1 represents a central area of the solid-state imaging device100, area ROI-3 represents an edge area (peripheral area) of thesolid-state imaging device 100, and area ROI-2 represents an areabetween area ROI-1 and area ROI-3. FIG. 1 shows the relative positionsof area ROI-1, area ROI-2, and area ROI-3 of the solid-state imagingdevice 100. It should be noted that the relative positions of areaROI-1, area ROI-2, and area ROI-3 may also be applied in the followingfigures.

FIG. 2A is a partial plane view illustrating area ROI-1 of thesolid-state imaging device 200 according to some embodiments of thedisclosure. FIG. 2B is a partial plane view illustrating area ROI-2 ofthe solid-state imaging device 200 according to some embodiments of thedisclosure. FIG. 2C is a partial plane view illustrating area ROI-3 ofthe solid-state imaging device 200 according to some embodiments of thedisclosure. FIG. 3A is a partial cross-sectional view illustrating areaROI-1 of the solid-state imaging device 200 according to someembodiments of the disclosure. FIG. 3B is a partial cross-sectional viewillustrating area ROI-2 of the solid-state imaging device 200 accordingto some embodiments of the disclosure. FIG. 3C is a partialcross-sectional view illustrating area ROI-3 of the solid-state imagingdevice 200 according to some embodiments of the disclosure.

In this embodiment, FIG. 3A may be the cross-sectional view of areaROI-1 of the solid-state imaging device 200 along line A-A′ or line B-B′shown in FIG. 2A. Similarly, FIG. 3B may be the cross-sectional view ofarea ROI-2 of the solid-state imaging device 200 along line C-C′ or lineD-D′ shown in FIG. 2B, and FIG. 3C may be the cross-sectional view ofarea ROI-3 of the solid-state imaging device 200 along line E-E′ or lineF-F′ shown in FIG. 2C. The relative positions of area ROI-1, area ROI-2,and area ROI-3 in FIG. 2A to FIG. 3C may also be referred to in FIG. 1.It should be noted that some components of the solid-state imagingdevice 200 may be omitted in FIG. 2A to FIG. 3C for the sake of brevity.

In some embodiments, the solid-state imaging device 200 may be formed ofa complementary metal-oxide semiconductor (CMOS) image sensor or acharge coupled device (CCD) image sensor, but the present disclosures isnot limited thereto. As shown in FIG. 3A to 3C, the solid-state imagingdevice 200 includes a substrate 101 which may be, for example, a waferor a chip, but the present disclosure is not limited thereto. Thesubstrate 101 has a front surface 101F and a back surface 101B oppositeto the front surface 101F. Multiple photoelectric conversion elements103 (e.g., photodiodes) may be formed in the substrate 101.

Referring to FIG. 3A to FIG. 3C, the substrate 101 has a plurality ofphotoelectric conversion elements 103. The photoelectric conversionelements 103 in the substrate 101 may be isolated from each other byisolation structures (not shown) such as shallow trench isolation (STI)regions or deep trench isolation regions. The isolation structures maybe formed in the substrate 101 using etching process to form trenchesand filling the trenches with an insulating or dielectric material.Although figures of the solid-state imaging devices of the embodimentsshow several pixels, actually the solid-state imaging devices haveseveral million or more pixels in the pixel array.

In some embodiments, the photoelectric conversion elements 103 areformed on the back surface 101B of the substrate 101, and a wiring layer105 is formed on the front surface 101F of the substrate 101, but thepresent disclosure is not limited thereto. The wiring layer 105 may bean interconnect structure that includes multiple conductive lines andvias embedded in multiple dielectric layers, and may further includevarious electric circuits required for the solid-state imaging device200. Incident lights may radiate onto the side of the back surface 101Band be received by the photoelectric conversion elements 103. Thesolid-state imaging device 200 as shown in FIG. 3A to FIG. 3C isreferred to as a back-side illuminated (BSI) imaging device, but thepresent disclosure is not limited thereto. In some other embodiments,the solid-state imaging device 200 may be a front-side illuminated (FSI)imaging device. The substrate 101 and the wiring layer 105 as shown inFIG. 3A to FIG. 3C may be inverted for FSI imaging device. In the FSIimaging device, incident lights radiate onto the side of the frontsurface 101F, pass through the wiring layer 105 and then are received bythe photoelectric conversion elements 103 formed on the back surface101B of the substrate 101.

As shown in FIG. 3A to FIG. 3C, in some embodiments, the solid-stateimaging device 200 may also include a high dielectric-constant (high-x)film 107 formed on the back surface 101B of the substrate 101 andcovering the photoelectric conversion elements 103. The material of thehigh-x film 107 may include hafnium oxide (HfO₂), hafnium tantalum oxide(HfTaO), hafnium titanium oxide (HMO), hafnium zirconium oxide (HfZrO),tantalum pentoxide (Ta₂O₅), other suitable high-x dielectric materials,or a combination thereof, but the present disclosure is not limitedthereto. The high-x film 107 may be formed by a deposition process. Thedeposition process is, for example, chemical vapor deposition (CVD),plasma enhanced chemical vapor deposition (PECVD), atomic layerdeposition (ALD), or another deposition technique. The high-x film 107may have a high-refractive index and a light-absorbing ability.

In some embodiments, the solid-state imaging device 200 may furtherinclude a buffer layer 109 formed on the high-x film 107. The materialof the buffer layer 109 may include silicon oxides, silicon nitrides,silicon oxynitrides, other suitable insulating materials, or acombination thereof, but the present disclosure is not limited thereto.The buffer layer 109 may be formed by a deposition process. Thedeposition process is, for example, spin-on coating, chemical vapordeposition, flowable chemical vapor deposition (FCVD), plasma enhancedchemical vapor deposition, physical vapor deposition (PVD), or anotherdeposition technique.

Referring to FIG. 3A to FIG. 3C, the solid-state imaging device 200 alsoincludes a color filter layer 120 disposed on the substrate 101 andabove the photoelectric conversion elements 103. In more detail, thecolor filter layer 120 includes a metal grid 111 formed on the bufferlayer 109 as shown in FIG. 3A to FIG. 3C, but the present disclosure isnot limited thereto. In some embodiments, the material of the metal grid111 may include tungsten (W), aluminum (Al), metal nitride (e.g.,titanium nitride (TiN)), other suitable materials, or a combinationthereof, but the present disclosure is not limited thereto. The metalgrid 111 may be formed by depositing a metal layer on the buffer layer109 and then patterning the metal layer using photolithography andetching processes to form a grid structure, but the present disclosureis not limited thereto.

Referring to FIG. 3A to FIG. 3C, the color filter layer 120 alsoincludes a color filter partition grid 113B and a plurality of colorfilter segments 115. The color filter segments 115 correspond to thephotoelectric conversion elements 103, and the color filter partitiongrid 113B is disposed between the color filter segments 115 and on themetal grid 111. In the embodiments of the present disclosure, the metalgrid 111, the color filter partition grid 113B and the color filtersegments 115 may collectively be referred to as the color filter layer120. In particular, the color filter partition grid 113B may be formedon and cover at least a portion of the metal grid 111, and the colorfilter segments 115 may be disposed in the respective spaces of thecolor filter partition grid 113B. The material of the color filterpartition grid 113B may include a transparent dielectric material thathas a low refractive index in a range from about 1.0 to about 1.99, andthe refractive index of the color filter partition grid 113B may belower than the refractive indexes of the color filter segments 115, butthe present disclosure is not limited thereto. Each color filter segment115 may correspond to one respective photoelectric conversion element103, but the present disclosure is not limited thereto.

Moreover, in some embodiments, the color filter segments 115 may includered (R) color filter segments 115R and green (G)/blue (B) color filtersegments 115GB arrayed by a suitable arrangement as shown in FIG. 3A toFIG. 3C. In some other embodiments, the color filter segments 115 mayfurther include white (W) or another color filter segment arrayed withred, green and blue color filter segments together in a suitablearrangement. The color filter segments 115 may have a top surface thatis level with the top surface of the color filter partition grid 113B,but the present disclosure is not limited thereto.

Referring to FIG. 3A to FIG. 3C, the solid-state imaging device 200further includes an optical waveguide layer 130 over the color filterlayer 120. As shown in FIG. 3A to FIG. 3C, the optical waveguide layer130 includes a waveguide partition grid 123A, a waveguide material 121in spaces of the waveguide partition grid 123A (and disposed above thephotoelectric conversion elements 103), and an anti-reflection film 123Bon the waveguide partition grid 123A and the waveguide material 121. Inmore detail, the waveguide partition grid 123A may be disposed tocorrespond to the color filter partition grid 113B, the waveguidematerial 121 and the waveguide partition grid 123A have a coplanar topsurface, and the anti-reflection film 123B is on the coplanar topsurface as shown in FIG. 3A to FIG. 3C, but the present disclosures isnot limited thereto.

In some embodiments, the material of the waveguide partition grid 123Amay include a transparent dielectric material that has a low refractiveindex in a range from about 1.0 to about 1.99, and the material of thewaveguide material 121 may include another transparent dielectricmaterial having a refractive index that is higher than the refractiveindex of the waveguide partition grid 123A, but the present disclosureis not limited thereto. In some embodiments, the refractive index of thewaveguide material 121 is in a range from about 1.1 to about 2.0. Insome embodiments, the waveguide partition grid 123A and theanti-reflection film 123B may be made of the same material and formedtogether in the same process step, but the present disclosure is notlimited thereto. In some other embodiments, the waveguide partition grid123A and the anti-reflection film 123B may be formed in the differentprocess steps.

In the embodiments of the present disclosure, the width of the top ofthe waveguide partition grid 123A may be larger than the width of thebottom of the waveguide partition grid 123A. That is, in thecross-sectional view of the solid-state imaging device 200 shown in FIG.3A to FIG. 3C, the waveguide partition grid 123A may be formed as aplurality of trapezoids, but the present disclosure is not limitedthereto.

In some embodiments, the waveguide partition grid 123A has a firstwaveguide portion 123A1 in area ROI-1 as shown in FIG. 2A and FIG.3A,and a second waveguide portion 123A2 (or 123A2′) corresponding to thefirst waveguide portion 123A1 in area ROI-2 (or area ROI-3). Moreover,the second waveguide width WW2 (or WW2′) of the top of the secondwaveguide portion 123A2 (or 123A2′) is greater than the first waveguidewidth WW1 of the top of the first waveguide portion 123A1. In thisembodiment, the second waveguide width WW2′ of the top of the secondwaveguide portion 123A2′ is greater than the second waveguide width WW2of the top of the second waveguide portion 123A2. That is, the secondwaveguide width WW2 of the top of the second waveguide portion 123A2 inarea ROI-2 (i.e., between the central area and the edge area of thesolid-state imaging device 200) or the second waveguide width WW2′ ofthe top of the second waveguide portion 123A2′ in area ROI-3 (i.e., theedge area of the solid-state imaging device 200) is greater than thefirst waveguide width WW1 of the top of the first waveguide portion123A1 in area ROI-1 (i.e., the central area of the solid-state imagingdevice 200).

As shown in FIG. 2A, FIG. 2B, FIG. 3A and FIG. 3B, for example, thefirst waveguide width WW1 of the top of the first waveguide portion123A1 may be in a range from about 0.15 μm to about 0.22 μm, while thesecond waveguide width WW2 of the top of the second waveguide portion123A2 may be in a range from about 0.17 μm to about 0.24 μm, but thepresent disclosure is not limited thereto. Similarly, as shown in FIG.2C and FIG. 3C, the second waveguide width WW2′ of the top of the secondwaveguide portion 123A2′ may be in a range from about 0.19 μm to about0.26 μm, but the present disclosure is not limited thereto. In someembodiments, the ratio (WW2/WW1 or WW2′/WW1) of the second waveguidewidth WW2 (or WW2′) of the top of the second waveguide portion 123A2 (or123A2′) to the first waveguide width WW1 of the top of the firstwaveguide portion 123A1 may be from about 1.05 to about 1.3, but thepresent disclosure is not limited thereto.

Furthermore, in the embodiment shown in FIG. 2A to FIG. 2C and FIG. 3Ato FIG. 3C, the first waveguide portion 123A1 in area ROI-1 and thesecond waveguide portion 123A2 (or 123A2′) in area ROI-2 (or in areaROI-3) enclose spaces corresponding to the red color filter segments115R. Since the second waveguide width WW2 (or WW2′) of the top of thesecond waveguide portion 123A2 (or 123A2′) is greater than the firstwaveguide width WW1 of the top of the first waveguide portion 123A1, thetop surface 121R of the waveguide material 121 corresponding to each ofthe red color filter segments 115R in area ROI-2 (i.e., between thecentral area and the edge area of the solid-state imaging device 200) orin area ROI-3 (i.e., the edge area of the solid-state imaging device200) is smaller than the top surface of the waveguide material 121corresponding to each of the red color filter segments 115R in areaROI-1 (i.e., the central area of the solid-state imaging device 200) asshown in FIG. 2A to FIG. 2C. As shown in FIG. 2B and FIG. 2C, the topsurface 121R of the waveguide material 121 corresponding to each of thered color filter segments 115R is smaller than the top surface 121GB ofthe waveguide material 121 corresponding to each of the green colorfilter segments and/or blue color filter segments 115GB in area ROI-2 orin area ROI-3.

In some embodiments, the position of the waveguide partition grid 123Ain area ROI-2 (i.e., between the central area and the edge area of thesolid-state imaging device 200) or in area ROI-3 (i.e., the edge area ofthe solid-state imaging device 200) may be shifted with respect to theposition of the color filter partition grid 113B by a shifting distancein a direction D. Here, the direction D is a horizontal direction thatis on a plane parallel to the top surface of the color filter layer 120.The shifting distance may be adjusted based on sensitivity, channelseparation, or another performance in area ROI-2 or in area ROI-3 of thesolid-state imaging device 200. In some embodiments, the shiftingdistance of the waveguide partition grid 123A may be consistent, but thepresent disclosures in not limited thereto. In some other embodiments,the shifting distance of the waveguide partition grid 123A may bevariable.

According to embodiments of the disclosure, an oblique incident lightradiating into the solid-state imaging device 200 with shifting in theposition of the waveguide partition grid 123A in area ROI-2 or in areaROI-3 may be guided into the color filter segment 115 and reach aposition near the central area of the photoelectric conversion element103. Therefore, the sensitivity in (or near) the edge area (peripheralarea) of the solid-state imaging device 200 may be enhanced.

Furthermore, the red color filter segments 115R may have highersensitivity than the green/blue color filter segments 115GB in areaROI-2 (i.e., between the central area and the edge area of thesolid-state imaging device 200) or in area ROI-3 (i.e., the edge area ofthe solid-state imaging device 200) due to the higher refractive index.In the embodiments of the present disclosure, the second waveguide widthWW2 (or WW2′) of the top of the second waveguide portion 123A2 (or123A2′) is set to be greater than the first waveguide width WW1 of thetop of the first waveguide portion 123A1, such that the difference ofthe sensitivities of the color filter segments 115 may be reduced.Therefore, the uniformity of the sensitivities in (or near) the edgearea (peripheral area) of the solid-state imaging devices 200 may beimproved.

FIG. 4A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device 300 according to some embodiments of thedisclosure. FIG. 4B is a partial cross-sectional view illustrating areaROI-3 of the solid-state imaging device 300 according to someembodiments of the disclosure. The relative positions of area ROI-1 andarea ROI-3 in FIG. 4A and FIG. 4B may also be referred to in FIG. 1. Itshould be noted that some components of the solid-state imaging device300 may be omitted in FIG. 4A and FIG. 4B for the sake of brevity.

Referring to FIG. 4A and FIG. 4B, in some embodiments, the photoelectricconversion elements 103 in the solid-state imaging device 300 may bearranged in a plurality of normal pixels P and a plurality of phasedetection auto focus pixels PDAF surrounded by the normal pixels P. Insome embodiments, each of the phase detection auto focus pixels PDAF maycorrespond to at least two of the photoelectric conversion elements 103,and each of the normal pixels P may correspond to one of thephotoelectric conversion elements 103, but the present disclosure is notlimited thereto.

In this embodiment, the metal grid 111 has different widths in differentareas of the solid-state imaging device 300. For example, as shown inFIG. 4A and FIG. 4B, the metal grid 111 has a first metal portion 111Ain area ROI-1 (i.e., the central area of the solid-state imaging device300) and a second metal portion 111B corresponding to the first metalportion 111A in area ROI-3 (i.e., the edge area of the solid-stateimaging device 300), but the present disclosure is not limited thereto.In some other embodiments, the second metal portion 111B of the metalgrid 111 may also be disposed in area ROI-2 (i.e., between the centralarea and the edge area of the solid-state imaging device 300).

In this embodiment, the first metal portion 111A and the second metalportion 111B of the metal grid 111 correspond to spaces between one ofthe phase detection auto focus pixels PDAF and the corresponding normalpixels P (i.e., the normal pixels P surrounding the phase detection autofocus pixel PDAF). Moreover, the second metal width MW2 of the secondmetal portion 111B is greater than the first metal width MW1 of thefirst metal portion 111A. In more detail, the second metal portion 111Bof the metal grid 111 may be partially below the color filter segments115 corresponding the normal pixels P in area ROI-3 as shown in FIG. 4B.That is, the color filter segments 115 may cover part of the secondmetal portion 111B of the metal grid 111 in the normal pixels P as shownin FIG. 4B. Instead, the first metal portion 111A of the metal grid 111may be fully covered by the color filter partition grid 113B in areaROI-1 as shown in FIG. 4A.

In some embodiments, the ratio (MW2/MW1) of the second metal width MW2of the second metal portion 111B to the first metal width MW1 of thefirst metal portion 111A may be about 1.2 to about 1.75, but the presentdisclosure is not limited thereto.

Since the normal pixels P surrounding the phase detection auto focuspixel PDAF may have higher sensitivity than other normal pixels P inarea ROI-3 (or in area ROI-2), the sensitivity in area ROI-3 (or in areaROI-2) may be non-balanced. In the embodiments of the disclosure, thesecond metal width MW2 of the second metal portion 111B is set to begreater than the first metal width MW1 of the first metal portion 111A,such that the difference of the sensitivities of the normal pixels P maybe reduced. Therefore, the uniformity of the sensitivities in (or near)the edge area (peripheral area) of the solid-state imaging devices 300may be improved.

In some embodiments, as shown in FIG. 4B, the color filter partitiongrid 113B has a grid width CW, and the grid width CW may be smaller thanthe second metal width MW2 of the second metal portion 111B in areaROI-3, but the present disclosure is not limited thereto.

FIG. 5A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device 400 according to some embodiments of thedisclosure. FIG. 5B is a partial cross-sectional view illustrating areaROI-3 of the solid-state imaging device 400 according to someembodiments of the disclosure. The relative positions of area ROI-1 andarea ROI-3 in FIG. 5A and FIG. 5B may also be referred to in FIG. 1. Itshould be noted that some components of the solid-state imaging device400 may be omitted in FIG. 5A and FIG. 5B for the sake of brevity.

Referring to FIG. 5A and FIG. 5B, in some embodiments, the photoelectricconversion elements 103 in the solid-state imaging device 400 may bearranged in a plurality of normal pixels P and a plurality of phasedetection auto focus pixels PDAF surrounded by the normal pixels P.Similarly, each of the phase detection auto focus pixels PDAF maycorrespond to at least two of the photoelectric conversion elements 103,and each of the normal pixels P may correspond to one of thephotoelectric conversion elements 103, but the present disclosure is notlimited thereto.

As shown in FIG. 5A and FIG. 5B, in some embodiments, the photoelectricconversion elements 103 in the solid-state imaging device 400 mayfurther be arranged in a plurality of additional normal pixels P1, andthe additional normal pixels P1 are separated from the phase detectionauto focus pixels PDAF by the normal pixels P.

In this embodiment, the waveguide partition grid 123A has differentwidths in different areas of the solid-state imaging device 400. Forexample, as shown in FIG. 5A and FIG. 5B, the waveguide partition grid123A has a first waveguide portion 123A1 in area ROI-1 (i.e., thecentral area of the solid-state imaging device 400) and a secondwaveguide portion 123A2 corresponding to the first waveguide portion123A1 in area ROI-3 (i.e., the edge area of the solid-state imagingdevice 400), but the present disclosure is not limited thereto. In someother embodiments, the second waveguide portion 123A2 of the waveguidepartition grid 123A may also be disposed in area ROI-2 (i.e., betweenthe central area and the edge area of the solid-state imaging device400).

In this embodiment, the first waveguide portion 123A1 and the secondwaveguide portion 123A2 of the waveguide partition grid 123A correspondto spaces between one of the phase detection auto focus pixels PDAF andthe corresponding normal pixels P (i.e., the normal pixels P surroundingthe phase detection auto focus pixel PDAF). Moreover, the secondwaveguide width WW2 of the top of the second waveguide portion 123A2 isgreater than the first waveguide width WW1 of the top of the firstwaveguide portion 123A1.

In some embodiments, as shown in FIG. 5B, the top surface 121A of thewaveguide material 121 corresponding to one of the normal pixels P issmaller than and the top surface 121B of the waveguide material 121corresponding to one of the additional normal pixels P1 in the areaROI-3 (or in area ROI-2), but the present disclosure is not limitedthereto.

Since the normal pixels P surrounding the phase detection auto focuspixel PDAF may have higher sensitivity than other normal pixels P (e.g.,the additional normal pixels P1) in area ROI-3 (or in area ROI-2), thesensitivity in area ROI-3 (or in area ROI-2) may be non-balanced. In theembodiments of the disclosure, the second waveguide width WW2 of the topof the second waveguide portion 123A2 is set to be greater than thefirst waveguide width WW1 of the top of the first waveguide portion123A1, such that the difference of the sensitivities of the normalpixels P may be reduced. Therefore, the uniformity of the sensitivitiesin (or near) the edge area (peripheral area) of the solid-state imagingdevices 400 may be improved.

In this embodiments, the waveguide partition grid 123A may have a thirdwaveguide portion 123A3 corresponding to one of the additional normalpixels P1 in area ROI-3 (i.e., the edge area of the solid-state imagingdevice 400) as shown in FIG. 5B. Moreover, the second waveguide widthWW2 of the top of the second waveguide portion 123A2 is greater than thethird waveguide width WW3 of the top of the third waveguide portion123A3, but the present disclosure is not limited thereto.

FIG. 6A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device 500 according to some embodiments of thedisclosure. FIG. 6B is a partial cross-sectional view illustrating areaROI-3 of the solid-state imaging device 500 according to someembodiments of the disclosure. The relative positions of area ROI-1 andarea ROI-3 in FIG. 6A and FIG. 6B may also be referred to in FIG. 1. Itshould be noted that some components of the solid-state imaging device500 may be omitted in FIG. 6A and FIG. 6B for the sake of brevity.

Referring to FIG. 6A and FIG. 6B, in some embodiments, the photoelectricconversion elements 103 in the solid-state imaging device 500 may bearranged in a plurality of normal pixels P and a plurality of phasedetection auto focus pixels PDAF surrounded by the normal pixels P.Similarly, each of the phase detection auto focus pixels PDAF maycorrespond to at least two of the photoelectric conversion elements 103,and each of the normal pixels P may correspond to one of thephotoelectric conversion elements 103, but the present disclosure is notlimited thereto.

In this embodiment, the color filter partition grid 113B has differentwidths in different areas of the solid-state imaging device 500. Forexample, as shown in FIG. 6A and FIG. 6B, the color filter partitiongrid 113B has a first color portion 113B1 in area ROI-1 (i.e., thecentral area of the solid-state imaging device 500) and a second colorportion 113B2 corresponding to the first color portion 113B1 in areaROI-3 (i.e., the edge area of the solid-state imaging device 500), butthe present disclosure is not limited thereto. In some otherembodiments, the second color portion 113B2 of the color filterpartition grid 113B may also be disposed in area ROI-2 (i.e., betweenthe central area and the edge area of the solid-state imaging device500).

In this embodiment, the first color portion 113B1 and the second colorportion 113B2 of the color filter partition grid 113B correspond tospaces between one of the phase detection auto focus pixels PDAF and thecorresponding normal pixels P (i.e., the normal pixels P surrounding thephase detection auto focus pixel PDAF). Moreover, the second color widthCW2 of the bottom of the second color portion 113B2 is smaller than thefirst color width CW1 of the bottom of the first color portion 113B1.

In the embodiment shown in FIG. 6A and FIG. 6B, the bottom surface 115B2of one of the color filter segments 115 enclosed by the second colorportion 113B2 (that corresponds to a phase detection auto focus pixelPDAF in area ROI-3 of in area ROI-2) is greater than the bottom surface115B1 of another of the color filter segments 115 enclosed by the firstcolor portion 113B1 (that corresponds to a phase detection auto focuspixel PDAF in area ROI-1).

Since the normal pixels P surrounding the phase detection auto focuspixel PDAF may have higher sensitivity than other normal pixels P inarea ROI-3 (or in area ROI-2), the sensitivity in area ROI-3 (or in areaROI-2) may be non-balanced. In the embodiments of the disclosure, thesecond color width CW2 of the bottom of the second color portion 113B2is set to be smaller than the first color width CW1 of the bottom of thefirst color portion 113B1, such that the difference of the sensitivitiesof the normal pixels P may be reduced. Therefore, the uniformity of thesensitivities in (or near) the edge area (peripheral area) of thesolid-state imaging devices 500 may be improved.

FIG. 7A is a partial cross-sectional view illustrating area ROI-1 of thesolid-state imaging device 600 according to some embodiments of thedisclosure. FIG. 7B is a partial cross-sectional view illustrating areaROI-3 of the solid-state imaging device 600 according to someembodiments of the disclosure. The relative positions of area ROI-1 andarea ROI-3 in FIG. 7A and FIG. 7B may also be referred to in FIG. 1. Itshould be noted that some components of the solid-state imaging device600 may be omitted in FIG. 7A and FIG. 7B for the sake of brevity.

Referring to FIG. 7A and FIG. 7B, in some embodiments, the photoelectricconversion elements 103 in the solid-state imaging device 600 may bearranged in a plurality of normal pixels P and a plurality of phasedetection auto focus pixels PDAF surrounded by the normal pixels P.Similarly, each of the phase detection auto focus pixels PDAF maycorrespond to at least two of the photoelectric conversion elements 103,and each of the normal pixels P may correspond to one of thephotoelectric conversion elements 103, but the present disclosure is notlimited thereto.

In this embodiment, the waveguide partition grid 123A has differentwidths in different areas of the solid-state imaging device 600. Forexample, as shown in FIG. 7A and FIG. 7B, the waveguide partition grid123A has a first waveguide portion 123A1 in area ROI-1 (i.e., thecentral area of the solid-state imaging device 600) and a secondwaveguide portion 123A2 corresponding to the first waveguide portion123A1 in area ROI-3 (i.e., the edge area of the solid-state imagingdevice 600), but the present disclosure is not limited thereto. In someother embodiments, the second waveguide portion 123A2 of the waveguidepartition grid 123A may also be disposed in area ROI-2 (i.e., betweenthe central area and the edge area of the solid-state imaging device600).

In this embodiment, the first waveguide portion 123A1 and the secondwaveguide portion 123A2 of the waveguide partition grid 123A correspondto spaces between one of the phase detection auto focus pixels PDAF andthe corresponding normal pixels P (i.e., the normal pixels P surroundingthe phase detection auto focus pixel PDAF). Moreover, the firstwaveguide width WW1 of the top of the first waveguide portion 123A1 isgreater than the second waveguide width WW2 of the top of the secondwaveguide portion 123A2.

As shown in FIG. 7A and FIG. 7B, in some embodiments, the top surface121A1 of the waveguide material 121 enclosed by the first waveguideportion 123A1 (that corresponds to a phase detection auto focus pixelPDAF in area ROI-1) is smaller than the top surface 121A2 of thewaveguide material 121 enclosed by the second waveguide portion 123A2(that corresponds to a phase detection auto focus pixel PDAF in areaROI-3 of in area ROI-2).

In the embodiments of the disclosure, the first waveguide width WW1 ofthe top of the first waveguide portion 123A1 is set to be greater thanthe second waveguide width WW2 of the top of the second waveguideportion 123A2, such that the uniformity of the sensitivities of thesolid-state imaging devices 600 may be improved.

FIG. 8A is a partial cross-sectional view illustrating the solid-stateimaging device 700 according to some embodiments of the disclosure. FIG.8B is a partial cross-sectional view illustrating the solid-stateimaging device 800 according to some embodiments of the disclosure.

It should be noted that some components of the solid-state imagingdevice 700 or the solid-state imaging device 800 may be omitted in FIG.8A and FIG. 8B for the sake of brevity.

As shown in FIG. 8A, the profile of each of the waveguide materials 121in the spaces may be a triangle shape; as shown in FIG. 8B, the profileof each of the waveguide materials 121 in the spaces may be an arcshape, but the present disclosure is not limited thereto. In someembodiments, each of the waveguide materials 121 in the spaces may havea profile including a rectangular shape, a triangle shape, other polygonshapes, an arc shape, or a combination thereof.

In summary, according to the embodiments of the present disclosure, byadjusting the widths of some components in the solid-state imagingdevice, the difference of the sensitivities of the color filter segmentsmay be reduced. Therefore, the uniformity of the sensitivities in (near)the edge or the peripheral area of the solid-state imaging devices maybe improved.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure. Therefore, the scope of protection should bedetermined through the claims. In addition, although some embodiments ofthe present disclosure are disclosed above, they are not intended tolimit the scope of the present disclosure.

Reference throughout this specification to features, advantages, orsimilar language does not imply that all of the features and advantagesthat may be realized with the present disclosure should be or are in anysingle embodiment of the disclosure. Rather, language referring to thefeatures and advantages is understood to mean that a specific feature,advantage, or characteristic described in connection with an embodimentis included in at least one embodiment of the present disclosure. Thus,discussions of the features and advantages, and similar language,throughout this specification may, but do not necessarily, refer to thesame embodiment.

Furthermore, the described features, advantages, and characteristics ofthe disclosure may be combined in any suitable manner in one or moreembodiments. One skilled in the relevant art will recognize, in light ofthe description herein, that the disclosure can be practiced without oneor more of the specific features or advantages of a particularembodiment. In other instances, additional features and advantages maybe recognized in certain embodiments that may not be present in allembodiments of the disclosure.

What is claimed is:
 1. A solid-state imaging device having a first areaand a second area surrounding the first area, comprising: a substratehaving a plurality of photoelectric conversion elements; a color filterlayer disposed on the substrate, and comprising a plurality of colorfilter segments corresponding to the plurality of photoelectricconversion elements; and an optical waveguide layer over the colorfilter layer, and comprising a waveguide partition grid, a waveguidematerial in spaces of the waveguide partition grid, and ananti-reflection film on the waveguide partition grid and the waveguidematerial, wherein a width of a top of the waveguide partition grid islarger than a width of a bottom of the waveguide partition grid.
 2. Thesolid-state imaging device as claimed in claim 1, wherein the waveguidepartition grid has a first waveguide portion in the first area and asecond waveguide portion corresponding to the first waveguide portion inthe second area, and a second waveguide width of a top of the secondwaveguide portion is greater than a first waveguide width of a top ofthe first waveguide portion.
 3. The solid-state imaging device asclaimed in claim 2, wherein the plurality of color filter segmentscomprise a plurality of red color filter segments and a plurality ofgreen color filter segments and/or blue color filter segments, the firstwaveguide portion and the second waveguide portion enclose spacescorresponding to the plurality of red color filter segments, and a topsurface of the waveguide material corresponding to each of the pluralityof red color filter segments is smaller than a top surface of thewaveguide material corresponding to each of the plurality of green colorfilter segments and/or blue color filter segments in the second area. 4.The solid-state imaging device as claimed in claim 2, wherein a ratio ofthe second waveguide width to the first waveguide width is from 1.05 to1.3.
 5. The solid-state imaging device as claimed in claim 1, whereinthe plurality of photoelectric conversion elements are arranged in aplurality of normal pixels and a plurality of phase detection auto focuspixels surrounded by the plurality of normal pixels, each of theplurality of phase detection auto focus pixels corresponds to at leasttwo of the plurality of photoelectric conversion elements, and each ofthe plurality of normal pixels corresponds to one of the plurality ofphotoelectric conversion elements.
 6. The solid-state imaging device asclaimed in claim 5, wherein color filter layer further comprises a metalgrid deposed between the plurality of color filter segments, the metalgrid has a first metal portion in the first area and a second metalportion corresponding to the first metal portion in the second area, anda second metal width of the second metal portion is greater than a firstmetal width of the first metal portion.
 7. The solid-state imagingdevice as claimed in claim 6, wherein the first metal portion and thesecond metal portion correspond to spaces between one of the pluralityof phase detection auto focus pixels and the plurality of normal pixelssurrounding the one of the plurality of phase detection auto focuspixels.
 8. The solid-state imaging device as claimed in claim 7, whereinthe plurality of color filter segments cover part of the second metalportion in the normal pixels.
 9. The solid-state imaging device asclaimed in claim 7, wherein the color filter layer further comprises acolor filter partition grid disposed between the plurality of colorfilter segments and on the metal grid, and the color filter partitiongrid has a grid width that is smaller than the second metal width of thesecond metal portion.
 10. The solid-state imaging device as claimed inclaim 6, wherein a ratio of the second metal width to the first metalwidth is 1.2 to 1.75.
 11. The solid-state imaging device as claimed inclaim 5, wherein the waveguide partition grid has a first waveguideportion in the first area and a second waveguide portion correspondingto the first waveguide portion in the second area, and a secondwaveguide width of a top of the second waveguide portion is greater thana first waveguide width of a top of the first waveguide portion.
 12. Thesolid-state imaging device as claimed in claim 11, wherein the firstwaveguide portion and the second waveguide portion correspond to spacesbetween one of the plurality of phase detection auto focus pixels andthe plurality of normal pixels surrounding the one of the plurality ofphase detection auto focus pixels.
 13. The solid-state imaging device asclaimed in claim 12, wherein the color filter layer further comprises acolor filter partition grid disposed between the plurality of colorfilter segments.
 14. The solid-state imaging device as claimed in claim13, wherein the plurality of photoelectric conversion elements arefurther arranged in a plurality of additional normal pixels separatedfrom the plurality of phase detection auto focus pixels by the pluralityof normal pixels, a top surface of the waveguide material correspondingto one of the plurality of normal pixels is smaller than and a topsurface of the waveguide material corresponding to one of the pluralityof additional normal pixels in the second area.
 15. The solid-stateimaging device as claimed in claim 5, wherein the color filter layerfurther comprises a color filter partition grid disposed between thecolor filter segments, the color filter partition grid has a first colorportion in the first area and a second color portion corresponding tothe first color portion in the second area, and a second color width ofa bottom of the second color portion is smaller than a first color widthof a bottom of the first color portion.
 16. The solid-state imagingdevice as claimed in claim 15, wherein the first color portion and thesecond color portion correspond to spaces between one of the pluralityof phase detection auto focus pixels and the plurality of normal pixelssurrounding the one of the plurality of phase detection auto focuspixels.
 17. The solid-state imaging device as claimed in claim 16,wherein a bottom surface of one of the plurality of color filtersegments enclosed by the second color portion is greater than a bottomsurface of another of the plurality of color filter segments enclosed bythe first color portion.
 18. The solid-state imaging device as claimedin claim 5, wherein the waveguide partition grid has a first waveguideportion in the first area and a second waveguide portion correspondingto the first waveguide portion in the second area, and a first waveguidewidth of a top of the first waveguide portion is greater than a secondwaveguide width of a top of the second waveguide portion.
 19. Thesolid-state imaging device as claimed in claim 18, wherein a top surfaceof the waveguide material enclosed by the first waveguide portion issmaller than a top surface of the waveguide material enclosed by thesecond waveguide portion.
 20. The solid-state imaging device as claimedin claim 1, wherein the waveguide material in the spaces has a profilecomprising a rectangular shape, a triangle shape, an arc shape, or acombination thereof.